1. Field of the Invention
The present invention relates to a monitoring method for properly collectively managing the operating states and operation records of a group of injection molding machines.
2. Description of the Related Art
It is known that the conformity of products can be determined by visually comparing product samples, extracted from a group of products obtained by repeating molding cycles, with conforming article samples. However, the determination of the conformity of the products by the sampling inspection is troublesome. Conventionally, therefore, molding process data (cushioning depth, injection time, etc.), detected in injection molding machines during the execution of the molding cycles and related to the conformity of the products, are cyclically printed or displayed on a screen under the control of a monitor unit, whereby they are offered as monitor data for an operator's monitoring (determination of product conformity) of the operating states of the injection molding machines.
In collectively managing a group of injection molding machines by using one monitor unit, monitor data for the individual injection molding machines are printed or displayed in rotation as detected by means of the monitor unit. The operator discriminates the conformity of an up-to-date molding cycle by determining whether or not up-to-date printed or displayed data are within a range for admission. In order to grasp the operation records of each injection molding machine, moreover, the operator picks out only those monitor data which are associated with the injection molding machine concerned, among other printed or displayed data, and checks the transition of the monitor data.
Although the conformity of the up-to-date molding cycle can be determined without a hitch by referring to the up-to-date monitor data, it is difficult to grasp the operation records of each injection molding machine. Thus, according to the conventional method described above, the monitor data for the group of injection molding machines are printed or displayed in rotation as detected, so that monitor data for another injection molding machine exist among the monitor data associated with the molding cycles successively executed by means of each injection molding machine. It is difficult, therefore, to pick out only the associated data among a lot of printed or displayed data. If the monitor data are delivered from each of those injection molding machines whose cycle times for each molding cycle are different with every predetermined molding cycle frequency, in particular, the delivery time intervals for the molding process data from the individual injection molding machines are different. Accordingly, the print intervals or display intervals for the monitor data for the individual injection molding machines are different from one another, so that it is more difficult to pick out the associated data. In displaying the monitor data on the screen, moreover, old monitor data are scrolled up, or new monitor data are overwritten on the old monitor data. It is impossible, therefore, to display sufficient monitor data for the management of the operation records of a large number of injection molding machines.